// converter
function decimal(fX,iPlaces){
 // chops down to 2 decimal places - brutally
 // iPlaces not used yet **************
    
    return Math.round(fX*Math.pow(10,iPlaces)) / Math.pow(10,iPlaces);
 //return Math.floor(fX*1000)/1000;
}

function log10(arg){
    return Math.log(arg)/Math.log(10);
}

function mw_to_dbm(){
    var mw = parseFloat(document.getElementById('i_mw').value);
    var dbm = 10*log10(mw);
    document.getElementById('t_dbm').value=decimal(dbm,3);
    document.getElementById('t_db2').value=decimal(dbm - 30,3);
}

function w_to_db(){
    var w = parseFloat(document.getElementById('i_w').value);
    var db = 10*log10(w);
    document.getElementById('t_db').value=decimal(db,3);
    document.getElementById('t_dbm2').value=decimal(db + 30,3);
}

function dbm_to_mw(){
    var dbm = parseFloat(document.getElementById('i_dbm').value);
    var mw = Math.pow(10,dbm/10);
    document.getElementById('t_mw').value=decimal(mw,3);
    document.getElementById('t_w2').value=decimal(mw/1000,3);
}

function db_to_w(){
    var db = parseFloat(document.getElementById('i_db').value);
    var w = Math.pow(10,db/10);
    document.getElementById('t_w').value=decimal(w,3);
    document.getElementById('t_mw2').value=decimal(w*1000,3);
}

function inch_to_mm(){
    var inch = parseFloat(document.getElementById('i_inch').value);
    var mm = inch * 25.4;
    document.getElementById('t_mm').value=decimal(mm,3);
    document.getElementById('t_m2').value=decimal(mm/1000,3);
}

function mm_to_inch(){
    var mm = parseFloat(document.getElementById('i_mm').value);
    var inch = mm / 25.4;
    document.getElementById('t_inch').value=decimal(inch,3);
}

function mile_to_m(){
    var mile = parseFloat(document.getElementById('i_mile').value);
    var m = mile * 1609;
    document.getElementById('t_m').value=decimal(m,3);
}

function m_to_mile(){
    var m = parseFloat(document.getElementById('i_m').value);
    var mile = m / 1609;
    document.getElementById('t_mile').value=decimal(mile,3);
}

function mile_to_m(){
    var mile = parseFloat(document.getElementById('i_mile').value);
    var m = mile * 1609;
    document.getElementById('t_m').value=decimal(m,3);
}

function m_to_mile(){
    var m = parseFloat(document.getElementById('i_m').value);
    var mile = m / 1609;
    document.getElementById('t_mile').value=decimal(mile,3);
}

function feet_to_m(){
    var feet = parseFloat(document.getElementById('i_feet').value);
    var m = feet * 0.3048;
    document.getElementById('t_mf').value=decimal(m,3);
}

function m_to_feet(){
    var m = parseFloat(document.getElementById('i_mf').value);
    var feet = m / 0.3048;
    document.getElementById('t_feet').value=decimal(feet,3);
}

function calc_fsl(){
    var f = parseFloat(document.getElementById('i_fsl_f').value);
    var mile = parseFloat(document.getElementById('i_fsl_mile').value);
    document.getElementById('t_fsl').value=decimal(20*log10(f)+20*log10(mile)+36.6,3);
}

function calc_dcr(){
    var h = parseFloat(document.getElementById('i_dcr_h').value);
    var angle = parseFloat(document.getElementById('i_dcr_angle').value);
    var width = parseFloat(document.getElementById('i_dcr_width').value);
    document.getElementById('t_dcr_inner').value=decimal(h/5280/Math.tan(Math.PI/180*(angle+width/2)),3);
    document.getElementById('t_dcr_outer').value=decimal(h/5280/Math.tan(Math.PI/180*(angle-width/2)),3);
}